Practical ecological knowledge for the temperate reader.

Red Alder - Alnus rubra

Emetic Inner Bark Wood; Dye (Red-Brown); Cooking tools Bark;Topical


"Alnus rubra is a deciduous Tree growing to 20 m (65ft 7in) at a fast rate.
It is hardy to zone (UK) 6. It is in flower in March, and the seeds ripen from Sep to October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind.It can fix Nitrogen.
Suitable for: medium (loamy) and heavy (clay) soils and can grow in heavy clay and nutritionally poor soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil. The plant can tolerate maritime exposure." [PFAF]

"Red alder is probably the most common deciduous tree in the southern part of British Columbia. The leaves normally have shallow, rounded teeth along their margins. The leaves of the cut-leaf mutant form have irregular, sharply pointed teeth and lobes, thus resembling some black oak leaves more than alder leaves." [E-flora]

Status: Native [E-flora]
General: "Deciduous shrub or tree, up to 25 m tall; axillary buds with stalks; bark scaly, often lichen-covered, yellowish-brown or grey-splotched with white." [IFBC-E-flora]
Leaves: "Alternate, deciduous, smooth, coarsely to irregularly toothed, the teeth pointing outwards, leaf margins rolled under, brownish in the fall." [IFBC-E-flora]
Flowers: "Inflorescence of male and female catkins which open before the leaves enlarge; male catkins with stalks." [IFBC-E-flora]
Fruits: "Small nutlets, with narrow-winged margins; female cones 1.5-2.5 cm long, egg-shaped." [IFBC-E-flora]

Habitat / Range "Moist woodlands, forests, floodplains and clearcuts in the lowland and montane zones; common in coastal BC; N to SE AK and S to CA." [IFBC-E-flora]

Ecological Indicator Information "A shade-intolerant, sub montane to montane, Pacific North American deciduous broad­leaved tree. An abundant species that grows in cool mesothermal climates on nitrogen-rich soils (Moder and Mull humus forms); its occurrence decreases with increasing elevation and continentality. Forms dense stands in the initial stages of primary succession on floodplains or secondary succession on water­shedding sites. Persists along streams and on water-collecting sites, usually associated with Lysichitum americanum; tolerates fluctuating groundwater tables. This fast -growing tree regenerates abundantly from seed on exposed mineral soil and from stump sprouts following cutting. May hinder regeneration and growth of conifers. Symbiosis with nitrogen­fixing Actinomycetes enhances the supply of available soil nitrogen. Suitable as a temporary nurse species for shade-tolerant conifers, especially on nitrogen-deficient sites; however, it may decrease both soil pH and base content of some soils. Characteristic of young­seral mesothermal forests." [IPBC-E-flora]


Emetic: The fresh inner bark is an emetic, often taken to induce vomiting if a poisonous substance has been ingested. Dry the bark unless you specifically want this action! [Schofield] The freshly harvested inner bark is emetic but is alright once it has been dried[172] [PFAF]

Edible Uses

Other Uses

Medicinal Uses


"Alnus rubra Bong. (Betulaceae) is a commonly occurring deciduous tree of the river valleys and moist coastal areas of the Pacific Northwest. Called the red alder tree, this species gets its name from the reddish-orange color which quickly develops on freshly exposed wood or bark. Indigenous peoples have used the bark of this tree for both coloring materials and medicines (1 -3). Medicinal uses of the bark have been varied and include purgatives, general tonics, and teas for the treatment of digestive and respiratory problems. A bark tea has also been used to relieve heart pain. Previous chemical investigations have led to the isolation of triterpe-noids (4, 5), the diarylheptanoid xyloside oregonin (6), and a procyanidin polymer (7). Oregonin and its aglycone were recently shown to be associated with the antibiotic activity (8) exhibited by a red alder bark methanol extract (9). In the present investigation of non-glycosidic diarylheptanoids of red alder bark, we report on the isolation and structural elucidation of the new compound 1-(3',4'-dihydroxyphenyl)-7-(4'-hydroxyphenyl)-4-hepten-3-one (1) and the known compound 1,7-bis(p-hydroxyphenyl)-4-hepten-3-one (2), Compound 2 has not been previously preorted in red alder. The isolation of these compounds from red alder bark has increased the known diversity of diarylheptanoid structures in this species which is finding renewed use as an indigenous medicine." [PDAR]

Betulin - Stem & Bark (AllHerb1998) [Duke2]

"Alder cambium was scraped off in the spring and eaten fresh with oil by all of the Salish groups on the Island. In some cases, strips of cambium were laid criss-cross to form a cake which was dried for winter (Barnett, 1955). The Saanich put the bark with camas bulbs in steaming pits to make the bulbs red (Suttles, 1951). Underhill (1944) mentions that alder bark was commonly smoked by some Northwest Coast groups. The Saanich used a reddish-brown dye made from alder bark boiled in water to colour fish nets, making them invisible to fish at night (Paul, 1968). This dye was used generally for staining baskets, cedar bark head rings, and the inside of canoes. The Saanich also made red tattoo marks with powder obtained from a burnt mixture of alder and cedar bark and a hemlock fungus (Jenness, ca. 1945). Many Northwest Coast Indian legends, particularly of the Kwakiutl (Boas, 1935), mention the chewing of aider bark to feign bleeding from the mouth, a sign of dying.
The even-grained wood was the most common dish-carving material on the Island. It was also used for arrow points, spoons, and other articles. The Songish used it for smoking fish, to which it imparted a pleasant flavour (Mitchell, 1968). The sap was used as a tonic by old Saanich people. It was thought to be good for the stomach (Suttles, 1951). The Songish soaked the sap in water and drank it to purify the blood (Mitchell, 1968). The bark was used by the Kwakiutl, and perhaps by the Coast Salish also, as a cure for tuberculosis (Boas, 1935). Mitchell (1968) states that alder buds were chewed and rubbed into sores and wounds by the Songish. They also burned the fruits to a powder and spread it over burns (Boas, 1890)." [Turner&Bell]

Bella Coola: Bark boiled, and a cupful of the decoction taken internally as a purgative.
Southern Carrier: Sap applied to cuts. Not used for a medicinal decoction.
Northern Carrier: Inside bark ground, steeped in water, and injected with a syringe made from the crop of a bird, for biliousness.
Gitksan: Bark and roots boiled for about six hours and the decoction drunk in the morning for a cough. Bark from the stem, but not from the roots, scraped, mixed with water, and the infusion taken internally, as an emetic and purgative, for headache and many other maladies. [Smith(1927)]


"Prefers a heavy soil and a damp situation[1, 11]. Grows well in heavy clay soils[11]. Tolerates very infertile sites[200]. A very wind resistant tree with excellent establishment in severely exposed sites, it tolerates severe maritime exposure[75, K]. The red alder is a very fast growing tree, even when planted in severe exposure[75, 229, K], but it is short-lived, dying when 60 - 80 years old[229]. Trees that are 5 years old from seed have reached 6 metres in height on a very exposed site in Cornwall, they are showing no signs of wind-shaping[K]. This is an important pioneer tree, quickly invading logged or burnt over sites, and providing ideal conditions for other trees to become established[229, K]. A very ornamental tree[1]. This species has a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[200]. Red alder has been estimated to fix as much as 300 kg of nitrogen per hectare[269]." [PFAF]

"Seed - best sown in a cold frame as soon as it is ripe and only just covered[200]. Spring sown seed should also germinate successfully so long as it is not covered[200, K]. The seed should germinate in the spring as the weather warms up. When large enough to handle, prick the seedlings out into individual pots. If growth is sufficient, it is possible to plant them out into their permanent positions in the summer, otherwise keep them in pots outdoors and plant them out in the spring. If you have sufficient quantity of seed, it can be sown thinly in an outdoor seed bed in the spring[78]. The seedlings can either be planted out into their permanent positions in the autumn/winter, or they can be allowed to grow on in the seed bed for a further season before planting them. Cuttings of mature wood, taken as soon as the leaves fall in autumn, outdoors in sandy soil." [PFAF]

Ectomycorrhizal Fungi

"Plants in this genus are involved in tri- or tetra-partite symbioses with nitrogen-fixing Frankia bacteria, EM fungi, and arbuscular mycorrhizal fungi (Chatarpaul et al. 1989; Molina et al. 1994). Along with Frankia bacteria, EM fungi co-dominate the roots of older Alnus individuals and play a significant role in nutrient acquisition and growth (Mejstrik & Benecke 1969; Molina et al. 1994; Yamanaka et al. 2003). Relative to other well-studied plant genera, Alnus hosts a low number of EM species, with only 50 species reported across the entire genus (Molina et al. 1994)." [EMF]
"... Alnus forests generally have lower sporocarp production and a greater proportion of host-specific species than adjacent forests (J.M. Trappe, pers. com.). Molecular-based studies have confirmed that Alnus EM assemblages are less diverse than those found on other hosts, although many of the same genera (e.g. Tomentella, Cortinarius, Lactarius) can dominate Alnus and other EM host forests (Pritsch et al. 1997; Beccera et al. 2005; Tedersoo et al. 2009)." [EMF]

A number of sporocarp and root tip morphotype studies have been conducted on the EM fungi associated with A. rubra (Neal et al. 1968; Molina 1979; Molina 1981; Miller et al. 1991). From these studies, it appears that A. rubra EM colonization is high and that assemblages are dominated by two Alnus-specific EM species, Alpova diplophloeus and Lactarius obscuratus. Only 11 EM species are known or suspected to associate with A. rubra across its geographic range, which is much lower than that of co-occurring EM hosts (e.g. Pseudotsuga menziesii may asso¬ciate with up to 2000 EM species (Trappe & Fogel 1977)). Host specificity of A. rubra EM assemblages was experimentally demonstrated by Miller et al. (1992), who found little overlap in the morphotypes of EM fungi colonizing A. rubra and P. menziesii seedlings grown in the same soils collected from different forest successional stages. [EMF]

At each site, we located a 900 m2 area for EM root tip sampling. Twenty 15 cm3 soil cores were taken from within 2 m of a randomly located A. rubra individual. An effort was made to take cores in areas where Frankia colonized roots were present to confirm host root identity. This was accomplished by removing the litter layer and first lightly raking in the vicinity of each randomly located tree. Frankia nodules are conspicuously colored and visible to the naked eye, so once a host root with a nodule was confirmed, the core was taken directly around it. [EMF]

Of the 385 root tips sequenced, 377 were successfully identified and 364 belonged to EM taxa. A total of 14 taxa were encountered across all sites.... Five taxa, Tomentella sp. 3, Alnicola escharoides, Lactarius cf. obscuratus, Tomentella sp. 1, and Alpova diplophloeus, accounted for 80 % of the EM tips sampled. The five dominant taxa were present at all four sites, while 5 EM taxa were unique to single sites..." [EMF]


Alterative; Astringent; Cancer(Epithelium); Emetic, Fumitory; Tonic.[Duke]

Specific Medicine Alnus Dose, from one to sixty minims.
Therapy—This agent combines both alterative and tonic astringent properties. It removes waste products, improves the tone of mucous structures and increases the secretory action of the glands of these structures. At the same time it prevents the flow of an excessive quantity of mucus into the stomach, and stimulates the flow of gastric juice and aids the digestion. It cures various forms of ulcerations in the mouth, or in the gastro-intestinal canal. It is advised in rhus poisoning. It has accomplished satisfactory cures in pustular and eczematous disease of the skin." [Ellingwood]
One source “…suggests the use of alnus in the treatment of syphilis.” It’s given “…in conjunction with echinacea and stillingia with successful results. It can be given as high as thirty drops at a dose, four times a day….” [Ellingwood]



Page last modified on Tuesday, August 8, 2023 10:37 AM